There are a number of different types of switches. One common type of switch is a plunger-type of switch, such as a push button switch or the like, that includes a plunger that is alternately depressed and released to actuate the switch. Other types of switches include inductive and Hall effect switches which are magnetically actuated. In this regard, inductive switches are generally actuated by an oscillating magnetic field, while Hall effect switches are generally actuated by a static magnetic field. Since the actuation of a plunger-type switch is dictated by the position of the plunger and the actuation of inductive and Hall effect switches is dictated by the strength and, at least in part, the position of the switch relative to the source of the magnetic field, each of these switches relies upon travel dependent switch actuation.
In addition to the type of actuation, switches can be categorized by the number of poles. Commonly a switch is either a single pole switch or a double pole switch, although switch design is not limited to only these configurations. A single pole switch is usually either a single pole, single throw or single pole, double throw. The internal configuration generally consists of a common contact paired with either a normally closed contact, normally open contact or both. In contrast, a double throw switch can have two, four or more movable common contacts with a corresponding number of normally closed and or normally open contacts. Thus, the initial actuation of a double throw switch would generally break the contact between the common contact(s) and the normally closed contact(s); with further actuation of the double throw switch plunger, establishing or making contact between the common contact(s) and the normally open contact(s).
Switches are used in a wide variety of different applications. For example, control panels, such as those employed by aircraft, space craft, automobiles and other vehicles, marine vehicles, industrial facilities and the like, often include a plurality of switches for providing certain types of information to the system based upon the state of the switch, such as closed or open. Switches are also often frequently used as limit switches and as interlocks in control and awareness systems.
It is desirable to test the performance of switches. For example, it may be desirable to test the performance of a switch prior to its installation so as to thereby qualify the switch. It may also be desirable to test the switch at one or more times during the lifetime of the switch to ensure that the switch is continuing to operate properly and to identify any changes in the performance of the switch over time. Finally, it may be desirable to test the performance of the switch following the failure of a system of which the switch is a portion.
Unfortunately, typical techniques for testing switches have been quite rudimentary and have generally only been performed during the design or initial qualification of a switch. Moreover, the conventional testing practices for switches have provided only limited information regarding the performance of a switch and may have somewhat questionable accuracy or at least less precision than is desired in certain demanding applications.